The present application is the U.S. National Phase of PCT/FR98/01777.
1. Field of the Invention
The present invention relates to a forceps device, such as, a biopsy forceps, that is to say, a forceps having two jaw-pieces capable of being moved away from each other, of being moved closer to each other and, while they are moving closer to each other, of cutting or detaching a specimen of body tissue which is seized between the two jaw-pieces of the forceps and which can subsequently be recovered outside the body.
The invention also extends to other instruments which can be used in medicine or in surgery, such as, for example, forceps instruments having no cutting effect, for providing a clamping effect, or retractors, or else scissors for surgical use, or any other instrument of this kind having two elements, at least one of which is capable of being moved away from and of being moved toward the other.
2. Discussion of the Background Information
The currently known biopsy forceps have two jaw-pieces capable of being moved away from each other or moved closer to each other, these being articulated on the end of an elongate, rigid or flexible tube, or sheath inside which a cable can slide. The cable is being provided at its other end with means for it to be maneuvered by the operator. These devices have articulated links designed to amplify movement between the control means formed by the cable and the jaw-pieces proper.
These forceps are mechanically complex and consist of at least about ten components. They are therefore expensive, difficult to fit and subject to wear and failures. At the linkage to the cable, they lead to torsional effects inducing fatigue in the cable which may cause it to break. Other components, too, may be exposed to excessive stresses, so that in the final analysis these forceps have a large number of drawbacks.
Moreover, the presence of the links, an articulation end of which extends along the axis of the forceps, makes it hard to add an auxiliary tool such as a barb extending along the axis of the forceps. Furthermore, it is extremely difficult to co-ordinate the movement of displacing the barb with the movement of opening the jaw-pieces of the forceps.
The present invention aims to remedy these drawbacks and to provide a forceps instrument, in particular a biopsy forceps, of extremely simple design, having a very limited number of components, eliminating any excessive force capable of leading to wear of the components, and enabling complex movements to be made, if required, in a simple manner, while maintaining very great precision in the movements of the jaw-pieces and also making it easy to use an auxiliary tool along the axis of the forceps.
The subject of the invention is a forceps instrument, in particular of the biopsy-forceps type, comprising, on the end of a sheath, two jaw-pieces, one of which, at least one of which is capable of being moved away from and of being moved toward the other when a maneuvering element slides axially in the end of the sheath.
The sheath may be optionally rigid. An elongated maneuvering element, preferably a cable, may slide in the sheath. The jaw-piece or jaw-pieces are capable of being moved away from and of being moved toward each other and have, in the extension of a part of the jaw-pieces acting as the jaws proper, an arm. The arm goes progressively toward the axis of the sheath so as to form a first, internal, inclined surface, going progressively toward the axis and facing the latter. Further the arm has second, external, inclined surface, also going progressively toward the axis and facing the internal surface of the end of the sheath. The arm has a convex excrescence capable of sliding substantially against the internal surface of the end of the sheath. The excrescence has facing the axis, a concave hollow cavity, wherein the sheath has, near its end beyond which the jaw proper extends, a transverse element, such as a rod against which the internal surface of the arm slides. The elongate maneuvering element terminates in a head housed in the concave hollow cavity so that, when the elongate maneuvering element or cable is moved toward the free end of the sheath, it pushes the jaw-piece back beyond the end, thus causing the internal surface of the arm, which slides over the transverse element, to pivot by a ramp effect, moving the jaw of the jaw-piece away from the other. Movement away from the other jaw is allowed by the inclination of the external surface which protrudes from the end of the internal surface of the sheath, the excrescence of the arm pivoting, during this movement, about the head while still being guided in said the sheath. Reverse movement of the maneuvering element caused the jaw-piece to move closer by a reverse movement. The transverse element includes a passage having an axis substantially parallel to the axis of the sheath, to accommodate an auxiliary tool between the two jaw-pieces.
According to particular embodiments:
the transverse element includes an interruption forming the passage and the transverse element is formed by two coaxial half-rods carried by the end of the sheath;
the transverse element includes an orifice forming the passage, which orifice extends substantially perpendicular to the axis of the transverse element;
the transverse element has two protuberances which are integral with the sheath and project from the internal surface of the end of the sheath;
each protuberance delimits a ramp whose normal is directed toward the end of the sheath, each ramp being extended by a shoulder for the sliding of the internal surface of the arm;
it includes an auxiliary tool passing through the passage of the transverse element;
the head is extended along the axis Axe2x80x94A of the sheath by the auxiliary tool, which is secured to it, which tool is accommodated such that it can move in translation in the passage of the transverse element when the maneuvering element is moved in the sheath;
the auxiliary tool is a rigid shaft tapered at its end and forming a barb;
the shaft is screwed into a threaded hole in the head;
the concave hollow cavity is substantially spherical and the head is a ball-and-socket joint;
the concave hollow cavity is at least partially in the form of a channel and the head is substantially cylindrical;
the jaws have reliefs on the outside designed for gripping a hollow object when said jaws are moved apart in the hollow object;
the jaw-pieces are electrically insulated from the outer surface of the sheath and the jaw-pieces have means for connection to a source of potential;
the two jaw-pieces are electrically insulated from one another and have means for connection to sources of different potentials; and
the head and the concave hollow cavity are spherical and form a ball-and-socket joint for the articulation of the jaw-pieces.
Preferably, the end of the sheath, in particular when the sheath is flexible, is formed by a rigid element fixed to one end of the sheath proper by one end of the rigid element, the other, free end of which supports the transverse element or rod, in two crenel-shaped extensions so that the geometrical axis of the rod is located near the bottoms of the crenels.
Preferably, the internal surface of the end of the sheath, or of its rigid end element, is planar, the internal and external surfaces of the arm or arms then being planar surfaces or geometrically cylindrical surfaces with a generatrix parallel to the internal surface of the end of the sheath and to the rod, and the external surface of the excrescence of the arm also being cylindrical.
Advantageously, the cross section of the end of the sheath, or of its rigid end element, delimits internally a rectangle, in particular a square, the internal surface of the end of the sheath, or of its rigid end element, being generated by one side of the rectangle.
Thus, by virtue of the invention, the internal surface of the jaw-piece arm may have a straight profile, or on the contrary, a profile which may vary, going progressively toward the axis of the sheath as it penetrates further into the sheath, thereby enabling the kinematics of the movement of the jaw-pieces away from each other to correspond to the shape of the ramp thus formed. The external face of the arms is also shaped when being moved closer to the axis, preferably so as to constantly slide on the end of the internal surface of the sheath and thus to avoid any free movement of the arm between the rod and the internal surface of the sheath.
Beyond the arm, the jaw-piece has the part forming the jaw proper, which may be of any shape suited to the desired use thereof.
The jaw of the jaw-piece may, for example, be produced in the form of a spoon having a cutting perimeter in the case of a biopsy forceps.
As a variant, the shape of the jaw may be that of a flat jaw-piece, for example in order to produce a gripping or clamping effect.
As another variant, the jaw may be in the form of a scissors cutting blade in order to produce a cutting instrument.
In general, the two jaw-pieces are symmetrical and undergo perfectly symmetrical movements with respect to a plane passing through the axis of the end of the sheath and the axis of the rod.
In a variant, one of the jaw-pieces may be produced so as to remain rotationally stationary and to undergo only a straight sliding movement while the other undergoes a sliding and pivoting movement with respect to the sheath.
During use, it may be desired for the jaw-piece, when moving away, also to move axially with respect to the element to be treated, for example, an organ. In this case, the sheath will remain stationary with respect to the organ to be treated and the maneuvering means, such as the cable, will undergo a translational movement in the sheath.
On the other hand, it may be desired for the jaw-pieces to undergo only a movement away from or toward the object or organ to be treated and, in this case, it is the maneuvering element which will remain stationary while the sheath will be moved translationally along this elongate maneuvering element.
For this purpose, the maneuvering element and the sheath include means which are designed to act, in turn, as means of holding one of the maneuvering element and the sheath in position with respect to the organ to be treated and as means of moving the other of these, respectively.
It will be understood that a forceps device has thus been produced which is mechanically very simple and which is composed of a very small number of components, namely the two jaw-pieces, the transverse rod, the head which terminates the sheath, and optionally a tubular section added onto the end of the sheath and forming the internal surface for guiding and receiving, on its end, the rod.
This results in easy assembly and dismantling, simple maintenance and almost complete freedom from the risks of breaking or of failure.
Other advantages and characteristics of the invention will appear on reading the following description, given by way of nonlimiting examples, and with reference to the appended drawings in which: